The field of the invention relates to ultrasonic devices and more particularly to ultrasonic probes used for therapeutic purposes.
Ultrasonic probes and probing is known. One use for such devices is in lithotrity (also commonly referred to as lithotripsy). Another use is in liposuction.
Lithotrity is a process for removing concretions, such as calculus stones, within human ducts such as the ureter or kidney. Under the process, a rigid probe is inserted into the body of the subject with a first end juxtaposed against the concretion. An ultrasonic signal is imposed onto the probe from a second end to break up the concretion.
In liposuction, a tip of the rigid probe is inserted under the skin of a patient against the fat of the patient. The ultrasonic signal imposed upon the probe dissolves the fat which may then be carried away by an irrigating fluid.
The ultrasonic signal is typically generated by use of an electrically stimulated ultrasonic motor which may be rigidly attached to the probe. A variable power supply is used to supply a controlling signal to the ultrasonic motor.
The probe used is often hollow and typically made of an impervious material such as stainless steel. A vacuum is often applied to an external end of the hollow tube to draw debris out of the body of a patient. In lithotrity, the tip used to contact and break up calculus stones is fabricated of a harder material than the remainder of the probe.
The length of the probe is usually selected to be an integer multiple of one-half wavelength at the operating frequency. Selecting the length of the probe as a integer multiple of one-half wavelength at the operating frequency (and appropriate selection of tube thickness and coupling components) causes the probe to function as a resonator. The use of the probe as a resonator reduces the net power required for effective operation.
While the use of ultrasonics for lithotrity or liposuction is effective, it is subject to a number of difficulties. For instance, lithotrity and liposuction devices are typically hand-held. To improve operator comfort and reduce an ultrasonic power requirement, the handle of such a device is typically isolated from the ultrasonic probe. The need for isolation between the handle and probe results in a high wear area subject to mechanical failure.
Further, it is often useful to provide a source of irrigation fluid near the tip of the ultrasonic probe. However, locating an irrigation tube near the tip of the probe often results in inadvertent contact between the probes resulting in a damping of ultrasonic energy. In order to improve the effectiveness of ultrasonic devices, a need exists for a means of providing irrigation fluid to a tip of an ultrasonic probe that is not subject to difficulties of prior devices.
An ultrasonic probe assembly is provided. The probe assembly includes a cannula and an ultrasonic probe disposed within the cannula. The probe assembly further includes a low-friction bushing disposed within the cannula and adapted to maintain the cannula and ultrasonic probe in a relatively fixed longitudinal relationship.